Soil is generally a mixture of four basic types: gravel, sand, clay and silt. Soil typically has low tensile and shear strength and its specific characteristics depend on whether it is currently dry or wet.
Pavement subgrades constructed with clay soils can cause significant pavement distress because of moisture-induced volume changes, and low subgrade strength [1]. Replacement of marginal soil with higher quality materials is not always the best alternative because of cost and environmental considerations [2]. Soil stabilization is an alternative method to improve the properties of weak soils and meet the design requirements [3]. Previous research indicated that waste and by-product cementitious materials such as fly ash, and calcined clay (metakaolin for example), crushed glass, blast furnace slag are suitable alternatives to replace cement as a soil stabilizer [4-7].